Orthopedic plate for use in the midfoot

Abstract

An orthopedic plate is specifically configured for implantation at the mid-foot. The plate has a first radius along the x-axis in the y direction and a second radius along the y-axis in the y direction The plate has an ring-shaped footprint with two diagonal sets, (one set of longer and one set of shorter) of opposing tabs. In each set of tabs, one tab includes a compression slot that extends and causes compression in a direction toward a screw hole in the opposing tab of the other set of tabs. The maximum length of the plate extends between the longer set of tabs, and an opening is included along this axis to allow viewing of the bone/bone fragments under the plate. The placement of the compression slots and the screw holes account for the progressively anterior placement of the cuneiforms and provides for compression in the medial direction. In a further embodiment, the plate is flat or includes a crease midway between the first and second tabs, which facilitates placement of the plate at the joint between the metatarsals and the cuneiforms.

1. A plate system which is capable of fixation of bone at the first and second or the second and third ray of the midfoot comprising a first and a second locking screw, a first and a second non-locking screw each having a head, and a plate having a top surface and a bone facing surface and having a first plate portion extending along a first length defining a first longitudinal axis and having a first end and a second end, the first end having a first terminal tab with a first compression slot having a first long axis and the second end including a second terminal tab with a first locking hole having a midpoint and a first midline, and the plate having a second plate portion extending along a second length defining a second longitudinal axis and having a third end and a fourth end, the third end having a third terminal tab along the second length with a second compression slot having a second long axis and the fourth end including a fourth terminal tab with a second locking hole having a midpoint and a second midline, each of the first and the second compression slots defining a first lateral edge and a second lateral edge which each include an inclined shoulder that slopes downward toward the bone facing surface of the plate parallel to the respective long axis of the respective compression slot, the midline of the first locking hole and the long axis of the first compression slot being aligned along the first longitudinal axis of the plate, the midline of the second locking hole and the long axis of the second compression slot being aligned along the second longitudinal axis of the plate, and the inclined shoulders of the each compression slot being engaged by a respective non-locking screw head to cause the translation of the respective non-locking screw along the respective long axis of the respective slot and towards the respective locking hole to cause compression in the direction of the respective long axis in the associated bone toward the respective locking hole in use, and a line connecting the midpoint of the first locking hole and the second locking hole being other than perpendicular to the first or second longitudinal axis. 
     
     
       2. A plate as set forth in  claim 1  wherein the bone facing surface of the plate has an inner surface which defines a first radius along the first length and a second radius along the second length. 
     
     
       3. A plate as set forth in  claim 1  wherein the plate further includes a central opening. 
     
     
       4. A plate as set forth in  claim 3  wherein the central opening is an oval. 
     
     
       5. A plate as set forth in  claim 1  wherein the contour of the plate forms a segment of a torroid. 
     
     
       6. A plate as set forth in  claim 1  wherein the plate is planar. 
     
     
       7. A plate as set forth in  claim 1  wherein the plate includes a crease. 
     
     
       8. A plate system for use in associated bone comprising a plate having a top surface and a bone-facing surface and a profile which comprises a first lateral side joined to a second lateral side, and at least one locking screw and at least one non-locking screw for each of the first lateral side and the second lateral side, each of the first side and the second side comprising a first end with a rounded tab and a second end with a rounded tab aligned along a respective longitudinal axis, each of the first end and the second end joined by a middle section, each of the first ends including a locking hole for the locking screw and the locking hole having a midpoint and a midline, and each of the second ends including a compression slot having a long axis, each of the compression slots defining a first lateral edge and a second lateral edge which include an inclined shoulder that slopes downward toward the bone facing surface of the plate parallel to the long axes of the respective compression slot, the midline of the respective locking hole and the long axis of the respective compression slot being aligned along the respective longitudinal axis of the first and second lateral side of the plate, each of the non-locking screws having a head and the inclined shoulders of the compression slots being engaged by the respective non-locking screw heads to cause the translation of the non-locking screws along the long axes of the slots and towards the respective locking hole to cause compression in the direction of the respective long axis in the associated bone toward the respective locking hole in use, and a line connecting the midpoint of the first locking hole and the second locking hole being other than perpendicular to the first or second longitudinal axis. 
     
     
       9. A plate system as set forth in  claim 8  wherein each of the first and the second tabs comprise a portion of a circle. 
     
     
       10. A plate system as set forth in  claim 9  wherein each of the middle sections has a width perpendicular to the respective longitudinal axis which is smaller that the diameter of either the first tab circle or the second tab circle. 
     
     
       11. A plate system as set forth in  claim 8  wherein the plate has a generally uniform thickness between the top surface and the bone-facing surface. 
     
     
       12. A plate system as set forth in  claim 11  wherein the plate includes a radius of curvature toward the bone-facing surface of the plate. 
     
     
       13. A plate system as set forth in  claim 12  wherein the plate is a section of a torroid. 
     
     
       14. A plate system as set forth in  claim 8  wherein the system further includes a drill guide which interacts with the locking hole to allow a pilot hole to be drilled in the associated bone at a desired angle. 
     
     
       15. A plate system as set forth in  claim 14  wherein the drill guide includes guides and the locking hole includes grooves which capture the guides to fix the angle of the drill guide. 
     
     
       16. A method of fusing bones, comprising:
 surgically accessing a bone, 
 selecting a plate which has a top surface and a bone-facing surface and a profile with bilateral mirror symmetry, the profile comprising a first lateral side and a second lateral side, each of the first lateral side and the second lateral side having first end which is a tab having a curved portion having a first diameter and a second end which is a tab having a curved portion having a second diameter which may be the same or different than the first diameter, the first and second end each being aligned along a respective longitudinal axis of the plate, and the first and second end each being joined by a middle section which has a width in the direction perpendicular to the respective longitudinal axis, the width being smaller than the first diameter and the second diameter, each of the first tabs including a locking hole for a locking screw, the locking hole having a midpoint and a midline, and each of the second tabs including an ovoid compression slot having a long axis, and each of the compression slots defining a first lateral edge and a second lateral edge which include an inclined shoulder that slopes downward toward the bone facing surface of the plate parallel to the respective long axis of the respective compression slot, each of the midline of the locking hole and the long axis of the compression slot being aligned along the respective longitudinal axis of the plate, and a line connecting the midpoint of the first locking hole and the second locking hole being other than perpendicular to the first or second longitudinal axis; 
 fixing a locking screw in each of the locking holes; 
 fixing a non-locking screw in each of the compression slots to cause compression in the associated bone toward the locking hole. 
 
     
     
       17. A method of fusing bones as set forth in  claim 16  wherein a drill guide is used to drill a pilot hole for the non-locking screw and to drill a pilot hole for the non-locking screw.